Pulley Decoupler Friction Pendulum for Torsional Vibration Noise
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Pulley decouplers for accessory drives in internal combustion engines face challenges in reducing torsional vibrations, which can lead to noise generation due to pendulum mass striking a stop during oscillation.
Innovation Solution
A pulley decoupler design incorporating a centrifugal pendulum device with pendulum masses acted upon by a friction force generated by a spring and friction element, preventing the pendulum mass from striking a stop and thus minimizing noise, while also utilizing a spring device and friction elements to dampen rotational vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a centrifugal pendulum device is used to damp torsional vibrations, then vibration damping performance is improved, but noise is generated due to pendulum mass striking a stop
Solution Approach 1:
A friction device is introduced as an intermediary between the pendulum mass and the stop. This friction device includes a friction element and a spring that presses the friction element against the pendulum mass. The friction device acts as a mediator that dissipates energy through friction before the pendulum mass can strike the stop, thereby eliminating noise while maintaining vibration damping effectiveness.
Solution Approach 2:
The potential harmful impact of the pendulum mass striking the stop is converted into a beneficial friction-based energy dissipation mechanism. Instead of allowing direct impact that generates noise, the friction device converts the kinetic energy of the striking pendulum mass into frictional heat, transforming a harmful noise-generating event into a beneficial damping mechanism that reduces vibrations without noise.
2Object-generated harmful factors
If a friction device is introduced to prevent pendulum mass from striking a stop, then noise is reduced, but device complexity increases
Solution Approach 1:
The friction device is nested within the existing centrifugal pendulum device structure. The friction element and spring are integrated into the pendulum assembly, with the friction element positioned between the pendulum mass and the stop. This nested arrangement allows the friction device to be incorporated without significantly increasing overall device complexity, as the components are housed within the existing structural envelope of the pendulum mechanism.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces noise and damping of torsional vibrations, allowing for a more uniform drive of accessories with reduced undesirable noise generation.
Implementation Method 1
the at least one pendulum mass being acted upon by a friction force which is produced by a first friction device having a first spring and at least one first friction element
Implementation Method 2
at least one pendulum mass which can be displaced under the action of centrifugal force relative to the centrifugal pendulum flange
Data Source
AI summary
A pulley decoupler for an accessory drive comprises input and output parts.The output part and the input part are rotatable about a common axis of rotation and are rotatable to a limited extent relative to one another.A centrifugal pendulum device is provided for damping torsional vibrations with a centrifugal pendulum flange that can be rotated about the axis of rotation and has at least one pendulum mass displaceable under centrifugal force relative to the centrifugal pendulum flange. The at least one pendulum mass is acted on by a friction force generated by a first friction device having a first spring and at least one first friction element.